Han Ho Jae, Heo Jung Sun, Lee Yun Jung, Min Jung Jun, Park Kwang Sung
Department of Veterinary Physiology, College of Veterinary Medicine, Chonnam National University, Gwangju, Korea.
Clin Exp Pharmacol Physiol. 2006 Mar;33(3):211-20. doi: 10.1111/j.1440-1681.2006.04348.x.
Abnormally high glucose levels may play an important role in early embryo development and function. In the present study, we investigated the effect of high glucose on 2-deoxyglucose (2-DG) uptake and its related signalling pathway in mouse embryonic stem (ES) cells. 2. 2-Deoxyglucose uptake was maximally inhibited by 25 mmol/L glucose after 24 h treatment. However, 25 mmol/L mannitol and dextran did not affect 2-DG uptake. Indeed, 25 mmol/L glucose decreased GLUT-1 mRNA and protein levels. The glucose (25 mmol/L)-induced inhibition of 2-DG uptake was blocked by pertussis toxin (a G(i)-protein inhibitor; 2 ng/mL), SQ 22,536 (an adenylate cyclase inhibitor; 10(-6) mol/L) and the protein kinase (PK) A inhibitor myristoylated PKI amide-(14-22) (10(-6) mol/L). Indeed, 25 mmol/L glucose increased intracellular cAMP content. 3. Furthermore, 25 mmol/L glucose-induced inhibition of 2-DG uptake was prevented by 10(-4) mol/L neomycin or 10(-6) mol/L U 73,122 (phospholipase C (PLC) inhibitors) and staurosporine or bisindolylmaleimide I (protein kinase (PK) C inhibitors). At 25 mmol/L, glucose increased translocation of PKC from the cytoplasmic fraction to the membrane fraction. The 25 mmol/L glucose-induced inhibition of 2-DG uptake and GLUT-1 protein levels was blocked by SQ 22,536, bisindolylmaleimide I or combined treatment. In addition, 25 mmol/L glucose increased cellular reactive oxygen species and the glucose-induced inhibition of 2-DG uptake were blocked by the anti-oxidants N-acetylcysteine (NAC; 10(-5) mol/L) or taurine (2 yen 10(-3) mol/L). 4. Glucose (25 mmol/L) activated p38 mitogen-activated protein kinase (MAPK) and p44/42 MAPK. Staurosporine (10(-6) mol/L), NAC (10(-5) mol/L) and PD 98059 (10(-7) mol/L) attenuated the phosphorylation of p44/42 MAPK. Both SB 203580 (a p38 MAPK inhibitor; 10(-7) mol/L) and PD 98059 (a p44/42 MAPK inhibitor; 10(-7) mol/L) blocked 25 mmol/L glucose-induced inhibition of 2-DG uptake. 5. In conclusion, high glucose inhibits 2-DG uptake through cAMP, PLC/PKC, oxidative stress or MAPK in mouse ES cells.
异常高的葡萄糖水平可能在早期胚胎发育和功能中起重要作用。在本研究中，我们调查了高葡萄糖对小鼠胚胎干细胞中2-脱氧葡萄糖（2-DG）摄取及其相关信号通路的影响。2. 处理24小时后，25 mmol/L葡萄糖对2-脱氧葡萄糖摄取的抑制作用最大。然而，25 mmol/L甘露醇和右旋糖酐不影响2-DG摄取。实际上，25 mmol/L葡萄糖降低了GLUT-1 mRNA和蛋白水平。百日咳毒素（一种G(i)蛋白抑制剂；2 ng/mL）、SQ 22,536（一种腺苷酸环化酶抑制剂；10(-6) mol/L）和蛋白激酶（PK）A抑制剂肉豆蔻酰化PKI酰胺-(14-22)（10(-6) mol/L）可阻断葡萄糖（25 mmol/L）诱导的2-DG摄取抑制。实际上，25 mmol/L葡萄糖增加了细胞内cAMP含量。3. 此外，10(-4) mol/L新霉素或10(-6) mol/L U 73,122（磷脂酶C（PLC）抑制剂）以及星形孢菌素或双吲哚马来酰亚胺I（蛋白激酶（PK）C抑制剂）可防止25 mmol/L葡萄糖诱导的2-DG摄取抑制。在25 mmol/L时，葡萄糖增加了PKC从细胞质部分向膜部分的转位。SQ 22,536、双吲哚马来酰亚胺I或联合处理可阻断25 mmol/L葡萄糖诱导的2-DG摄取和GLUT-1蛋白水平抑制。此外，25 mmol/L葡萄糖增加了细胞活性氧，抗氧化剂N-乙酰半胱氨酸（NAC；10(-5) mol/L）或牛磺酸（2×10(-3) mol/L）可阻断葡萄糖诱导的2-DG摄取抑制。4. 葡萄糖（25 mmol/L）激活了p38丝裂原活化蛋白激酶（MAPK）和p44/42 MAPK。星形孢菌素（10(-6) mol/L）、NAC（10(-5) mol/L）和PD 98059（10(-7) mol/L）减弱了p44/42 MAPK的磷酸化。SB 203580（一种p38 MAPK抑制剂；10(-7) mol/L）和PD 98059（一种p44/42 MAPK抑制剂；10(-7) mol/L）均阻断了25 mmol/L葡萄糖诱导的2-DG摄取抑制。5. 总之，高葡萄糖通过cAMP、PLC/PKC、氧化应激或MAPK抑制小鼠胚胎干细胞中的2-DG摄取。
